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c. P. SCHWARZ.

LEAF SPRIN GL APPLICATION FlLED MAR. 29 1917.

1 ,3 1 2, 1 39. Patented Aug. 5, 1919.

' M. JZffq/ney o".

TUE COLyMBIA PLANOORAPH (10., WASHINdTuN, 15. c.

NI STATES PATENT Q C Y S NIIK T P4 1 S W JQFI a eat. a t 1 To all whomit may concern: l

Be it known that I, *(loNsr N'rmn P. Sorrwknz, a citizen of the UnitedStates, residing at Cleveland, in the county of Cuyahoga and State ofOhio, haveinvented a new and useful Improvement in Leaf- Springs, ofwhich the following is a specification. y

This invention relates to leaf springs of the kind comprisinga mainspring and a counter spring which cooperate to absorb shocks to whichthe composite spring is subjected.

The objects of the invention are to provide a composite spring of thiskind with an insert placed between the main spring and the counterspring to increase the shock absorbing ability of the spring and toprevent noise during the operation of the spring.

' In the accompanying drawings Figure 1 is a side elevation of a springembodying the invention before the parts of the spring are drawntogether.

Fig. 2 is a similar view thereof showing the parts of the spring inoperative relation to each other.

Fig. 3 is a transverse sectional elevation thereof on line 33, Fig. 2.

It is well known that the shock absorbing ability of a leaf springvaries as the pressure acting on the engaging faces of the spring leavesor relatlvely movable parts of the spring, as the coefiicient offriction acting between the relatively movable parts of the spring, andas the amount of'relative movement between engaging faces. To increasethe shock absorbing ability of leaf springs, means have been providedfor in creasing the friction between relatively movable parts of aspring. Means have also been provided for increasing the displacement orrelative movement of the parts, for example, by means of the structureshown in my co-pending application No. 76,109, filed February 4th, 1916,and means have also been devised for increasing the pressure acting onthe engaging faces of the leaves of the spring by use, for example, of acounter spring. It has been found, however, that the use of a counterspring causes noises which are objectionable, these noises being due toa coming together of the counter spring and main sprin after having beenseparated by a severe s ock. For this purpose, an insert oi: the kindhereinafter de Patented Aug. 5, 1919. Applicationfi1edMarch29Q1917JSeria1NoJi15 8,249. 1

scribed isplaced between the main spring and counter spring, which notonly increases plurality of spring 1 leaves and which 3 has theusuallooped end portions or eyes a for securing the spring totheshackles or bolts ofra vehicleq: Thisfspring as well as the counterspring may be of the kind commonly used" in which adjacentspringl leavesare in contact, or it may be provided with inserts between the springleaves, as shown in my above mentioned application No. 76,109. Erepresents the counter spring, which as shown in Fig. 1, normally has acurvature opposite to that of the main spring, and which preferably alsoconsists of a plurality of spring leaves. G represents an insert adaptedto be secured between the two parts A and B of the spring. The insertmay be made 'of any suitable material having a yielding or flexiblesurface so that no noise will be made by the coming in contact of theparts of the spring and the insert after these parts have been separatedby a shock. The insert should also be of a material which will notbecome disintegrated by the flexing or bending of the spring, such asleather, paper, fabric of any kind, fiber, wood, or any other suitablematerial, and should preferably be of some light substance so as not tomaterially increase the weight of the composite spring. Since the shockabsorbing ability of the composite spring depends upon the thickness ofthe insert, it is desirable to make the insert as thick as ispracticable. The insert should also be of sulficient length and breadthto keep the adja cent faces of the main and counter spring out ofcontact at all times. i

The main and counter springs with the insert in place between the sameare then pressed together and securely clamped in place by any suitablemeans, such as clips or shackles D so that the longest leaf of eachspring part touches the insert throughout the length of the insert. Whenthe composite spring is assembled, the counter spring increases thepressure acting on the contacting faces of the main spring leaves andthus increases the ability of this spring to absorb .Arepresentsthemain:spring,-which may, as: in the COIlStI'llCtlOIl l shown, l vcomprise a increasing the displacement or relative movement between thetwo spring parts, and

eliminates the principal objection to springs of this' kind asheretofore constructed, namely the noise caused by the coming togetherof the two parts of the spring.

I- claim" as my invention 1. A- composite leaf spring comprising a mainspring and a counter spring, said ysp'rings being normallyof 'oppositecurvature, an insert between said two: spring parts, said insert havingyielding surfaces which prevent noise when the spring partsVco'ntacttherewith A and being of lower specific gravity than steel,-and -means for clampingsaid colinter spring and said main I springintofengagementwith said insert.

"2. A composite leafspringco'niprising a main spring. and a counterspring, said springs being normally of opposite curvature and beingplaced together with their concave faces adjacent to each other, anlllSGI'i) between said ad1acent faces for hold- 7 ingsaid counter springout of engagement with said inain spring, said insert being of a'niaterial having flexible surfaces adjacent contact with said insertthroughout their .ad acent faces when said spring 1s m a normalposition.

Witness my hand this 19th day of March,

CONSTANTINE P. SCHWARZ.

Witnesses WM. J. -SHANER, E. P. CHAMBERLIN.

{Copies of this pate nt may-be obtaine'difor five cents each, byaddressing the Commissioner of Patents,

7 Washington, I). 0.

